Torque release tool for screwthreaded units



E. w. RISTOW 2,475,518 TORQUE RELEASE TOOL FOR SCREW THREADED UNITS July 5,1949.

Filed June 3, 1946 INVENTOR EDWARD W.RISTOW A oRNEYs Patented July 5, 1949 2-;475,51s iroRQUn'RjELEAjsE Toh 'rmtschhw:

THREADED'UNITS 5 EdtvitidWf Ri s'tow,- 'Milwaukee; Wis., assignor to" I Milwai1kee Electric Tool 5 Corporation. 'Milwau kee; Wis.

"Animation June-'3, 194s-,"*se'r1a1 Nef ttigiio 2 Claiins. (ohms-45) 5 tor ue re eese'emteh ftr' controlling the drive of the tool"from"afpowr actiiat'ed spindle.

"A' "further object of "hay invention 'is to provide a. power driven spindle with a cupped or recessed head having radial-apertures carrying loosely nibiinted cluth' ballsl therein, engageable with a spring ci'inti'olld "iiiaster bttll or" conically nosed plug. lwhereby springfhie's'suref exerted upon the master ball will force ar'idinaintain theclutch bhlls in pockets iorined in'a sleeve; 'j'o'urnaled' on saidreeessed Head.tdeffectclutching. v th' the'a-bo've'afid bth'er'objects'in view,- which will appear" asfthe dsrip'tidn" proceeds, 'the invention resides 'in the novel construction, coinbiha'tion' and arrangement of "baits, substantially as hereinafter described and more particularly defihed byth'e appendd'claiins, it being understood I that 's ich 'e ehgee the: precise embodiin'ent'of'the herein disclosed invention may be inadefas came within the scope'of the claims.

In the accohipaiiyingfdrawings ;is 'illustrated one complete: ex'a'rhple of l the physical enibodiment 3 of the p'resent invention constructed according to the'best modeso far" gie visediw the practical-application=ofthe principles thereof.

In the drawings:

Fig. 1 represents a screw'driverembodying the features of my invention the same being broken away and-in"sectionesifidicated bylines i-l of Figs. 3 to 6 inclusive.

Fig. 2 wa -fragmentary-lQngitudinaI sectional viewillustrating the torque release clutch balls in-theirdisengaged position.

."Fig53 is a cross"section"through the tool and keyd couplingthe section being indicatdby' line 3--3 of Fig. 1.

Fig. 4 is another cross sectional view, as indicated by line 4-4 of Fig. 1.

Fig. 5 is another cross sectional View through ;he mechanism, the section being indicated by ine 5-5 of Fig. 1.

Fig. 6 is a further cross sectional View through he same illustrating the ball clutch in its funcioning position, the section being indicated by ine 6-6 of Fig. 1; and

Fig. 7 is a. further cross sectional view illus- 55 *Gfis iicased in a lioiising fli which housing in "threaded union with the shell I. The ou'th-"face' of'th'e ter ball for controlling the driving balls 5, I may. in some instances, substitute therefor a cam headed plug of the conical or spherical type.

Brazed or otherwise secured to the mouth of the sleeve II is an annularly recessed or undercut keyed coupling l9, as indicated in Figs. 1 and 3 of the drawings. The keyed coupling is provided with a polygonally shaped aperture 20 for the reception of the shank 20 of a screw driver tool. Hence, it will be noted, when the screw driver tool is removed, any standard screw driver may be inserted through "said aperture for engagement with the kerf of the adjusting plug l5, whereby said plug is conveniently rotated to vary the pressure of the coil spring upon the back face of the master ball.

The shank of the screw driver tool is formed with an annular recess 20 for the reception of a ball 2| which extends through an aperture'in the coupling 19 and is pressed inwardly by a circular spring 21. This coupling connection, however, forms no .partof my invention,.it simply being a means for frictionally holding the tool shank within the coupling;

From the foregoing description, in operation the spindle is normally in rotation. The tension spring 18 exerts a force-on the ball i! and an equal force on thescrew plug 15, which force is transmitted through the threads I l to effect the engagement of the-sleeve flange .and housing shoulder annular surfaces. Thus, normally, .jaws in and is are -nt-engaged,1- enabling the operator to rotate the tool carrying sleeve H byhand to effect the proper mating of the tool. and the work (not shown),-this without shutting off his source of power. v

The spring pressure onsthe master ball L1 resolves-itself radially andequally against balls .5, which may be three or more in number, causing said balls'to enter semicircular ypockets :L-whereupon sleeve-collar B and head aware driven as a unit.

-From the foregoing description, when .thelmachine is .put into use, the end chisel face ofthe tool 120 isinserted into the kerf of ascrew (not shown) either of the woodor machine type. .The device is then given a slight depression movement in actual alignment with thescrew head. "This action will cause the housingandassociatedparts to =move downward, in opposition to .the .coil spring, whereby the teeth-of the sleeve-collar and sleeve will be intermeshedtofiect apositive locking between these parts.

It is understood, .in the above referred tooperation, 'the master 'ball, beingjin engagement with'the balls 5, will radially force said'balls into the sleeve-collar semicircular. pockets 1, as vbest shown'in Figs. 1 and 6 of the drawings, whereby a1positiveclutch connection effected tocause rotation of the'scr'ew driver tool, which rotation willcontinue until such time as thehead of the screw has exerted the desired tension .orldownward pressure upon the screw. When this .de-, sired pressure is exerted, the :coil spring, being properly adjusted as to "tension, will yield under overload force. This yielding resisting force is due to the fact that the circular pockets in the sleeve-collar will force the balls 5 inwardly, upon further rotation of said spindle. The halls will thus roll towards the center of the head and, in so doing, will force the master ball I! outwardly, whereby said balls will radially contract until their outer surfaces are aligned with the outer circumference of the head, to thus free the clutch connection between the power spindle and sleeve,

as best shown in Figs. 2 and 7 of the drawings, whereby the'screw driver tool will come to a stop.

This breaking connection between the tool and the driving power will be determined by the tension set for the coil spring. Hence, the screw element may be accurately given the desired tightening seat pressure, which pressure is entirely automatic.

While I 'have shown and described the mechanism as it applies to a-portable hand tool of the air .or electric type, it is apparent that the device may be applied to any source of rotatin power such as a drill press or flexible shaft, "It is also obvious that the screw driving. tool may be either of the .male or female type.

While I have specifically described a positive clutch connection between the sleeve-collar and sleeve, in some instances this clutch connection may be dispensed with. The parts comprising the collar and sleeve may bea single unit. It is also obviousthat the rotation of the screw driver I tool may be reversed for extracting screw memhers.

'1. 'A torque 'releaseclutch comprising a centrally recessed-driven :head "having radial apertures therein, a toothed sleeve-collar rotatably mounted upon the head, pocketsin the sleevecol-lar, clutch balls mounted in'the'head apertures engageable withthe sleeve-collar pockets, a cam member looselymountedjin the recessed head vengageable with -the'clutch balls, ,a flange toothr carrying sleeve engageable with the sleeve-collar teeth, and a tension spring engaging the master ball.

Atorque release clutch'comprising a centrally recessed driving head .having apertures therein, a sleeve-collar rotatably -m0unted thereon, pockets-in "the sleeve-collar, clutch balls mounted in the "head apertures "engageable with thesleeve collar pockets, a cam member mounted in "the head recess engageable "with the clutch balls,'and arr adjustable tension spring engaging the cam member.

' EDWARD W. RISTOW.

REFERENCES -CITED The following referemces are of record in the. file of this patent:

. UNITED sTA'rEsrnTENTs 

